After much research, I just purchased a Staub "5 quart" oval cocotte.
In the midst of my research, I discovered by checking Staub's website for the stock number, that some places list the ,same cocotte as having 4.5 quarts capacity, and some 5. I found the same thing with a few of the other sizes such as 6 3/4 quarts and 7 quarts.
Here's an example taken from Amazon of the 4.5/5 quart models.
Listed as 4.5 quarts, item model number: 1102942 http://www.amazon.com/Staub-Quart-Ova...
Listed as 5 quarts, item number: 1102925 http://www.amazon.com/Staub-Quart-Ova...
The Staub website lists each of these models as having a 4.5 capacity.
I wound up purchasing what is described as a "5 quart" from Amazon and am happy with the color, price and what I assume is really, a 4.5 quart cocotte.
I didn't contact either Amazon or Staub about the discrepancy, as I think both are pretty reputable and it just perplexes me. I know there has to be a valid reason for the discrepancy, but right now, it's elusive to me. I thought I would as you very knowledgeable folks if you can tell me why this is?